This invention relates in general to a method and apparatus for controlling movement of an animal and, in particular, to a method and apparatus for electronically preventing an animal from approaching an area to be protected from intrusion by the animal.
Electronic animal control systems commonly either contain an animal within a perimeter delineated by a wire, or are of the form of an xe2x80x9celectronic tether.xe2x80x9d When using a typical perimeter device, the animal is deterred from crossing the perimeter by applying an electronic correction signal to the animal after it approaches within a preselected distance of the wire. Detecting the proximity of the wire is typically performed by use of a sensor on a collar unit provided on the animal, where the sensor senses an electromagnetic field around the wire. The electronic correction is supplied by the collar unit and is typically either an acoustic signal or an electric shock.
xe2x80x9cElectronic tetherxe2x80x9d systems use a similar collar unit but, in this case, the electronic correction is applied to the animal when the distance between a collar unit and a central transmitter is too great, as measured by the strength of a received electromagnetic signal. The animal receives correction when it has strayed too far from the central transmitter.
These electronic animal control systems are relatively unsophisticated devices, and are not well suited to use indoors. For example, it would appear that an outdoor perimeter device could be used indoors to deter an animal from approaching a door, thus keeping the animal in the room. However, such a perimeter unit requires that a perimeter wire be laid around the entire room, which significantly reduces the area within the room in which the animal may roam without receiving correction. Additionally, present electronic control systems are unable to distinguish which of several animals requires attention, assuming that more than one animal is provided with a collar unit, and the control systems, therefore, treat all animals in the same manner. Typically, no record is kept of animal activity, for example how many corrections the animal received in any particular time period.
A conventional collar unit is generally an autonomous unit which is battery powered. The lifetime of the battery is affected by many factors, including the number of corrections which are provided to the animal. The user is not provided with information regarding the number of corrections the animal receives, nor with the current state of the battery. Thus, the user may be unaware that the battery has lost charge, and the user has to guess when a new battery is needed in the collar unit. Additionally, a conventional collar unit is provided with metal contact pins of fixed length. These pins, typically of fixed length, may have to be changed according to the thickness of the coat of the animal. For example, a dog with a thin coat, such as Doberman Pinscher, requires shorter pins, while a dog with a long coat, such as an English Sheepdog, requires longer pins. Current collar units provide the user with a number of sets of pins, which the user has to connect manually to the collar unit. The pins would require changing if, for example, a collar unit normally used on a dog with a thin coat, were to be used on a dog with a thicker coat.
Indoor pet control systems are available which repel a pet from a prescribed area. Such systems typically use ultrasonic transmitters to generate a continuous repulsion signal. The animal is dissuaded from entering the area simply because the volume of the ultrasonic signal is uncomfortably high. Systems of this type suffer from several deficiencies, including a lack of intelligence, so the system cannot distinguish between different animals which may approach the protected area. Since the ultrasonic signal is generally continuous, the animal is subjected to constant annoyance, even when outside the area being protected.
Therefore, there is a need for an electronic animal control system which does not confine an animal to only a portion of a room when the desired restriction is simply to prevent it from leaving the room. There is also a need for a more sophisticated system which is able to warn the user when an animal receives correction or when the battery in the collar unit is low. There is a general need for a more sophisticated approach to electronically controlling an animal which can provide the user with many advanced features not available with current systems, including the management of a number of containment spaces, and where each containment space may be pre-programmed to be applicable to each particular animal present. There is also a need for a collar unit having improved metal contact pins which do not require repeated adjustment or reinstallation by the user.
To overcome the limitations in the prior art, such as those described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention is directed to a method and apparatus for determining whether the animal is located inside or outside of a bounded area.
The invention may be viewed as a portable unit for detecting whether an animal is inside or outside of a bounded area. The portable unit includes sensing circuitry configured to detect a boundary signal delineating the bounded area and configured to detect a polarity indicator of the boundary signal. The sensing circuitry is further configured to provide a polarity signal in response to the polarity indicator, the polarity signal having a delay defined by the polarity of the polarity indicator. A processor is included and is configured to receive the polarity signal and determine whether the animal is inside or outside of the bounded area by detecting the length of the polarity signal delay
The invention may be viewed as a method for detecting whether an animal is inside or outside of a bounded area. The method involves detecting a boundary signal delineating the bounded area with a portable unit worn by the animal. A polarity indicator of the boundary signal is detected. A polarity signal is provided in response to the polarity indicator, the polarity signal having a delay defined by the polarity of the polarity indicator. Whether the animal is inside or outside of the bounded area is determined by detecting the length of the polarity signal delay.